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    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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    <script>
        // 给一段文章中的全部指定词语进行过滤
        var str = 'asdasdSMasdasdasdSMsdasdasdSMsadasd'
        for(var i= 0;i<3;i++){
            var res =str.replace("SM","**")
            str = res;
        }
        var newstr =str.substr(0,29);
        console.log(newstr);
    </script>
</body>
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